Preparation method of clopidogrel hydrogen sulfate I

The invention relates to a preparation method of a drug compound, in particular to a preparation method of clopidogrel hydrogen sulfate I. The method provided by the invention comprises the following steps: 1, mixing clopidogrel salt with an organic solvent and water, adding an acid binding agent to react to generate free alkali of clopidogrel, extracting the water layer with the organic solvent, combining the organic phases and carrying out concentration; and 2. adding the organic solvent into the free alkali of clopidogrel obtained after concentration, dropwise adding sulfuric acid into the solution for reaction based on the molar ratio of the sulfuric acid to the free alkali of clopidogrel, filtering the reactant and drying the filtrate to obtain the crystal form of clopidogrel hydrogen sulfate I, wherein the molar ratio is (0.8-1.05):1.